1. Field of the Invention
The present invention relates to a master disk for magnetic transfer, in particular, relates to a master disk for magnetic transfer suitable for transferring magnetic information such as format information to a magnetic disk used for a hard disk device or the like.
2. Description of the Related Art
In a magnetic disk (hard disk) used in a hard disk drive rapidly diffused recently, format information or address information are written, generally, after it is delivered from a magnetic disk maker to a drive maker and before it is assembled to the drive. The writing can be performed by a magnetic head, but a method for transferring the information collectively from a master disk in which the format information or the address information is written, is effective and preferable.
The magnetic transfer method for collectively transferring, magnetically transfers information (for example, a servo signal) included in the master disk to a slave disk by disposing a magnetic field generating device such as an electromagnet device and a permanent magnet device to apply a transfer magnetic field on one or both surfaces, while allowing the master disk and the disk (slave disk) to be transferred to be in close contact with each other. In addition, in order to perform magnetic transfer accurately, it is very important to allow the master disk and the slave disk to be in close contact with each other evenly and without spacing.
As the master disk used for the method for magnetic transfer, a disk in which a concavo-convex pattern corresponding to information signal is formed on the substrate surface, and a magnetic layer is coated on the surface of the concavo-convex pattern, is generally used. The master disk for magnetic transfer is generally manufactured by coating a magnetic layer on the surface of the concavo-convex pattern, after the steps of: electroforming on an original plate in which information is formed with the concavo-convex pattern, and for laminating a metal disk made of the electroformed layer on the original plate to transfer the concavo-convex pattern on the metal disk; releasing the metal disk from the original plate; and punching through the released metal disk in a predetermined size (for example, see Japanese Patent Application Laid-Open No. 2001-256644).